Technicians at the NASA Shuttle Logistic Depot in Cape Canaveral, Fla.,
began forensic engineering testing on May 3 on a faulty power distribution box,
called a Load Control Assembly 2 (LCA-2). It was removed earlier in the day
from the aft compartment of space shuttle Endeavour on Launch Pad 39A
at NASA’s Kennedy Space Center.

Technicians are trying to determine what caused the power box to fail. Heaters
on a fuel line for Endeavour’s auxiliary power unit-1 (APU-1) did not work
on April 29, prompting the launch team to scrub the shuttle’s first
launch attempt for the STS-134 mission to the International Space Station.
The heaters receive power through the LCA-2.

Technicians also are preparing to replace the power box and any other
associated hardware that is faulty and retest the system before
Endeavour’s next launch attempt is scheduled.